Most biotherapeutics can induce unwanted immune responses with possible consequences on safety and efficacy whereby these responses vary in frequency and severity (Buttel, I. C. et al., Biologicals 39 (2011) 100-109; COMMITTEE FOR MEDICINAL PRODUCTS FOR HUMAN USE (CHMP), EMEA Guideline on Immunogenicity Assessment of Biotechnology-derived Therapeutic Proteins).
The formation of anti-drug antibodies (ADA) might result in altered pharmacokinetics, loss or reduction of efficacy, neutralization of natural counterparts as well as general immune and hypersensitivity reactions, including serum sickness/type III hypersensitivity reaction/immune complex-mediated disease (Buttel, I. C. et al., Biologicals 39 (2011) 100-109; COMMITTEE FOR MEDICINAL PRODUCTS FOR HUMAN USE (CHMP), EMEA Guideline on Immunogenicity Assessment of Biotechnology-derived Therapeutic Proteins).
Serum sickness like syndrome, as a result of the formation of ADA-D complexes, is a well-known adverse event and has been reported for a variety of biologicals in preclinical studies (Ponce, R. et al., Regul. Toxicol. Pharmacol. 54 (2009) 164-182) and in clinical practice (COMMITTEE FOR MEDICINAL PRODUCTS FOR HUMAN USE (CHMP), EMEA Guideline on Immunogenicity Assessment of Biotechnology-derived Therapeutic Proteins; Dreyfus, D. H. et al., Ann. Allergy Asthma Immunol. 96 (2006) 624-627; Gamarra, R. M., J. Emerg. Med. 30 (2006) 41-44; Goto, S. et al., Int. J. Hematol. 89 (2009) 305-309; Hansel, T. T. et al., Nat. Rev. Drug Discov. 9 (2010) 325-338; Pilette, C. et al., J. Allergy Clin. Immunol. 120 (2007) 972-973; Tamilvanan, S. et al., J. Drug Target 18 (2010) 489-498).
For marketed drugs, the features of major reactions such as serum sickness or severe allergic reactions are diagnosed clinically. In cases where adverse events follow administration of the implicated mAb, the reactions are attributed to an antibody response (COMMITTEE FOR MEDICINAL PRODUCTS FOR HUMAN USE (CHMP), EMEA Guideline on Immunogenicity Assessment of Biotechnology-derived Therapeutic Proteins). Indeed, only very limited data can be found where the formation of ADAs was investigated and correlated with the clinically observed signals (Goto, S. et al., Int. J. Hematol. 89 (2009) 305-309).
Given the potential seriousness of immunogenicity, the EMEA emphasized the importance of confirmation and characterization of ADA formation (COMMITTEE FOR MEDICINAL PRODUCTS FOR HUMAN USE (CHMP), EMEA Guideline on Immunogenicity Assessment of Biotechnology-derived Therapeutic Proteins).
Assessment of immunogenicity is typically conducted using immunoassays which are designed to detect ADAs (Mire-Sluis, A. R. et al., J. Immunol. Methods 289 (2004) 1-16; Shankar, G. et al., J. Pharm. Biomed. Anal. 48 (2008) 1267-1281; Koren, E. et al., J. Immunol. Methods 333 (2008) 1-9).
Information of ADA incidence, however, does until now not enable a profound correlation with clinical findings and altered pharmacokinetics.
The amount and size of the formed ADA-drug complexes is dependent on several parameters, e.g. ADA and drug concentration/ratio as well as epitope and valence (Abbas, A. K. and Lichtman, A. H., Diseases caused by immunity responses: Hypersensitivity and Autoimmunity, in: Saunders (2003); Murphy, K. et al., Janeway's Immunobiology, in: Garland Science, Taylor & Francis Group, LLC (2008)).
The complex size and charge is an important determinant of complex clearance or induction of adverse events. Typically, larger complexes are cleared by the reticulo-endothelial system, small complexes usually do not trigger inflammation, whereas intermediate size complexes may fix complement and can cause tissue damage (Abbas, A. K. and Lichtman, A. H., Diseases caused by immunity responses: Hypersensitivity and Autoimmunity, in: Saunders (2003); Murphy, K. et al., Janeway's Immunobiology, in: Garland Science, Taylor & Francis Group, LLC (2008); Mannik, M., Serum Sickness and pathophysiology of immune complexes, in: Clinical Immunology: Principles and Practices, Rich R. R., Fleisher T. A. S. B. D., Shearer W. T., Strober W. (eds.) 1062-1071 (1996); Sicherer, S. H., Leung D. Y. M., Serum Sickness, in: Nelsons textbook of pediatrics, Kliegman R. M., Behrman R. E., Jenson H. B. J., Stanton B. F. (eds.), Saunders Elsevier, pp. 985-986 (2007). Furthermore, charge of the complexes is an important factor for tissue deposition of the complexes (Abbas, A. K. and Lichtman, A. H., Diseases caused by immunity responses: Hypersensitivity and Autoimmunity, in: Saunders (2003); Mannik, M., Serum Sickness and pathophysiology of immune complexes, in: Clinical Immunology: Principles and Practices, Rich R. R., Fleisher T. A. S. B. D., Shearer W. T., Strober W. (eds.) 1062-1071 (1996)).
For a profound evaluation of an ADA response, potentially formed ADA-drug complexes should be characterized with regard to size and charge. In addition, if an endogenous counterpart of the drug exists, information of whether the formed ADAs are cross-reactive to these molecules and whether endogenous counterparts are also part of the complex is a valuable information. Furthermore, structural characterization of the antigen/drug in the immune complexes provides information for the pathogenesis.
Coyle et al. report the detection and isolation of immune complexes in multiple sclerosis cerebrospinal fluid (Journal of Neuroimmunology 15 (1987) 97-107). Chromatofocusing combined with the ELISA technique—a sensitive method for the analysis of immune complexes is reported by Kneba, M., et al. (J. Immunol. Meth. 61 (1983) 233-243). Matousovic, K., et al. report IgA-containing immune complexes in the urine of IgA nephropathy patients (Nephrology Dialysis Transplantation 21 (2006) 2478-2484). Circulating immune complexes in rabbits surviving rinderpest virus infection is reported by Rattan, B., et al. (Acta Vir. 38 (1994) 105-110). In WO 2008/031532 an anti-drug antibody assay is reported. Stubenrauch, K., et al., report the evaluation of a generic immunoassay with drug tolerance to detect immune complexes in serum samples from cynomolgus monkeys after administration of human antibodies (J. Pharm. Biomed. Anal. 52 (2010) 249-254). In WO 2011/056590 assays for the detection of anti-TNF drugs and autoantibodies is reported. Wang Shui Long et al. report the analysis of anti-drug antibodies (ADA) to Adalimumab in patient serum using a novel homogeneous mobility shift assay (Am. J. Gastroent. 105 (Sup 1, 2010) S444-S445. In EP 2 354 792 a method for detecting anti-drug antibodies is reported. Lambert, P. H., et al. report a WHO collaborative study for the evaluation of eighteen methods for detecting immune complexes in serum (J. Clin. Lab. Immunol. 1 (1978) 1-15). Methods for measuring circulating immune complexes are reported by Levinson, S. S. et al. (Clin. Immunol. Newsletter 3 (1987) 39-42).